Antioxidants in foods By: Adiba Hasnat

There is a hint in the name anti-oxidant.

In a nutshell an antioxidant is a molecule that prevents the oxidation of other molecules by allowing itself to be oxidized instead

They can be nutrients and enzymes Oxidation – is a chemical reaction

within a redox reaction where a molecule loses its electrons to an oxidizing agent

(“What are antioxidants?”, 2001)

So what is an antioxidant?

In our normal biological processes that undergo oxidation (such as digestion, cellular respiration and metabolism) as a byproduct we produce a high amount of free radicalsFree radicals – are unstable, highly reactive atoms or molecules free floating in our body that have a charge because they are missing one or more electrons or have one too many

(Healthwise, 2009)

Why do we need antioxidants in our body?

Free radical examples:

• O2- superoxide anion• OH- hydroxyl radical• transition metals such

as iron and copper• nitric acid• ozone

Why are free radicals so dangerous?

1. Free radicals are unstable and highly reactive the one that are negatively charged will most likely “steal” the electrons it needs from other stable molecules in the body (oxidization)

2. When the free radical becomes reduced the stable molecule it oxidized now becomes a free radical itself and this will onset a chain reaction of redox reactions

3. This chain reaction will go on to disrupt many important processes that occur in the cell and the body in general

CHAIN REACTION(Healthwise, 2009)

Antioxidants prevent oxidation of stable compounds by neutralizing free radicals.

2 methods:

Chain-breaking – when a free radical initiates a chain reaction an antioxidant molecule such as beta-carotene, vitamin C and E stabilizes the radical by providing it with the electron it needs to become neutral. In the process of neutralizing the free radical the antioxidant becomes oxidized and therefore needs to be continuously replaced.

Preventive – is the method that uses antioxidant enzymes like superoxide dismutase, catalase and glutathione peroxidase to prevent oxidation by reducing the amount of initiating free radicals that exist in the first place.

(WebMD, 2006)

How do antioxidants work?

Because antioxidants are oxidized in the process of neutralizing free radicals they need to be constantly replenished. They body’s method of replenishing its necessary supply of antioxidants is by obtaining these important molecules through the foods that we eat.

Antioxidant relation to food

Vitamin E – is the most abundant fat-soluble antioxidant in the body. - It is a general name for all the different isomers of tocopherol

EX. alpha-tocopherol is a specific isomer that helps protect cell membranes (which are mostly fatty acids) from damage by free radicals Foods: nuts and seeds, whole grains, green leafy vegetables, vegetable oil and liver oil.

(Parnes, 2002)

Antioxidant: Vitamin E

Vitamin C – is the most abundant water-soluble antioxidant used in the body- It acts primarily in cellular fluid and neutralizes free radicals in that watery environment

Foods: citrus fruits, green peppers, leafy green vegetables, strawberries and tomatoes.

(Parnes, 2002)

Antioxidant: Vitamin C

Beta-carotene – another water-soluble antioxidant used in the body

Target function: maintain eye health

Foods: orange coloured foods -- carrots, cantaloupe, pumpkin, apricots, squash and mango, kale, collard greens, spinach

(Parnes, 2002)

Antioxidant: Beta-carotene

Antioxidants prevent the harmful effects free radicals have on the body’s natural processes and functions

Oxidative stress – an imbalance between the production of reactive oxygen(a radical) and the body’s ability to reduce the amounts of harmful radicals present or repair the damage that they cause. (Worden, 2011)

Due to the undesired oxidization, free radicals cause: - Destruction of cell membrane (fatty acids) and proteins - DNA mutation caused by the oxidation of important sections of DNA

strands- Prematurely age skin by causing the breakdown of collagen in skin cells (Healthwise, 2009)

What damaging processes do Antioxidants prevent?

Even though there are many benefits to using antioxidants, too much can also cause harm. 1. Too much antioxidants:- Increase the risk of mortality - Increase the risk of cardiovascular disease - increased risk of hemorrhagic strokeWhy? The body produces its own antioxidants so adding too many external antioxidants can disrupt the homeostatic balance your body tries to maintain which leads to complications.

(Coila, 2011)

Risks of antioxidants

1. Reduce the amount of free radicals in your body2. Reduce the risk of developing certain diseases such as; cancer, heart disease, stroke, cataracts, Parkinson's, Alzheimer's and arthritis (Phillip, 2012)3. Prevent direct cell damage caused by the chain reaction that free radicals initiate 4. Reduce the signs of aging by preventing the oxidation of your skin cells 5. Improves digestion 6. Relieves asthma and allergy symptoms (Antioxidants for health and longevity, 2009)

Benefits of Antioxidants

What are antioxidants? (2001). Retrieved March 20, 2013, from fitday: http://www.fitday.com/fitness-articles/nutrition/vitamins-minerals/what-are-antioxidants-where-can-i-find-them.htmlAntioxidants for health and longevity. (2009). Health Benefits of Antioxidants. Retrieved March 24, 2013, from Antioxidants for health and longevity: http://www.antioxidants-for-health-and-

longevity.com/benefits-of-antioxidants.htmlCoila, B. (2011, June 27). Live strong . Retrieved March 20, 2013, from The Effects of Too Much

Antioxidants: http://www.livestrong.com/article/480352-the-effects-of-too-much-antioxidants/Healthwise. (2009, April 14). Retrieved March 24, 2013, from What Free Radicals Do To Our Body and Health!: http://thehive.modbee.com/node/13459Parnes, R. (2002, November 26). Antioxidants. Retrieved from How stuff works: http://health.howstuffworks.com/wellness/food-nutrition/facts/antioxidant4.htmPhillip, J. (2012, October 20). Diet high in antioxidants slashes heart disease risk in women. Retrieved March 20, 2013, from Natural news: http://www.naturalnews.com/037402_antioxidants_heart_disease_women.htmlWebMD, L. (2006, April 22). How antioxidants work. Retrieved March 20, 2013, from Web MD: http://www.webmd.com/food-recipes/features/how-antioxidants-work1?page=3Worden, J. (2011, November 31). Antioxidants and oxidative stress. Retrieved March 24, 2013,

from Netdoctor: http://www.netdoctor.co.uk/focus/nutrition/facts/oxidative_stress/oxidativestress.htm

References